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Hardhat

Introduction

Hardhat is a flexible development environment for building, testing, and deploying smart contracts on Polkadot. Its task runner and plugin system support organizing contract code, running tests, managing deployments, and adding custom tooling. This page demonstrates how to set up a Hardhat project for Polkadot Hub.

Prerequisites

Before setting up Hardhat, make sure the following are installed:

  • Node.js (Hardhat requires an LTS Node version, even major numbers like 18.x, 20.x, or 22.x)
  • A package manager like npm, pnpm, or yarn

Initialize a Hardhat Project

  1. Create a directory to hold your project files:

    mkdir hardhat-example
cd hardhat-example

  2. Initialize a Hardhat project:

    This single command sets up your project, installs Hardhat (and optionally the Toolbox), and intializes the project:

    npx hardhat@^2.27.0 init

    This single command sets up your project, installs Hardhat (and optionally the Toolbox), and intializes the project:

    pnpm dlx hardhat@^2.27.0 init

    These commands manually set up your project, install Hardhat (and optionally the Toolbox), and initializes the project:

    # Initialize a new Node.js project
yarn init -y

# Install Hardhat and the Hardhat Toolbox locally
yarn add --dev hardhat@^2.27.0 @nomicfoundation/hardhat-toolbox

# Initialize a Hardhat project
npx hardhat init

  3. You will be prompted to select certain configurations for your project. To quickly create a working setup, you can accept the default answers, which will create a JavaScript project, initialize it in the current directory, add a .gitignore, and install all dependencies.

After completing the setup, your Hardhat project will be fully initialized with all necessary files and dependencies. You'll see the following core components in your project:

  • contracts: Stores your Solidity smart contracts.
  • ignition: Contains deployment modules for safely deploying your contracts to various networks.
  • test: Contains test files that validate contract functionality.
  • hardhat.config.js | .ts: Defines your project's settings, including networks, compiler options, and plugins.

Configure Hardhat for Polkadot Hub

To use Hardhat with Polkadot Hub, define the network configuration in your hardhat.config.ts file:

hardhat.config.ts
import type { HardhatUserConfig } from 'hardhat/config';
import '@nomicfoundation/hardhat-toolbox';

// If you want to use a variable for your private key
import { vars } from 'hardhat/config';

const config: HardhatUserConfig = {
  solidity: '0.8.28',
  networks: {
    polkadotTestnet: {
      url: 'https://services.polkadothub-rpc.com/testnet',
      chainId: 420420417,
      accounts: [vars.get('PRIVATE_KEY')],
    },
  },
};

export default config;

Tip

To define a configuration variable for your private key, run:

npx hardhat vars set PRIVATE_KEY

Hardhat will prompt you to enter your private key and store it so it can be referenced in your configuration file.

Where to Go Next

  • Guide Deploy a Basic Contract

    Ready to start using Hardhat? Learn how to compile, test, and deploy a basic contract.

    Get Started

  • Guide Deploy an ERC-20

    Walk through deploying a fully-functional ERC-20 to Polkadot Hub using Hardhat.

    Get Started

  • Guide Deploy an NFT

    Walk through deploying an NFT to Polkadot Hub using Hardhat.

    Get Started

  • Guide Create a DApp

    Learn step-by-step how to build a fully functional dApp that interacts with a smart contract deployed via Hardhat.

    Get Started

Last update: January 14, 2026
| Created: January 14, 2026